SPIV를 이용한 조류발전터빈의 후류유동 계측 및 상호상관면 중첩법을 이용한 SPIV 해석 알고리즘 개발

Abstract

Influences of efficiency of current turbine on wake field are investigated by towed underwater Stereoscopic Particle Image Velocimetry (SPIV) system. The TSR conditions for wake measurement were chosen based on the torque coefficient and flow filed in various downstream locations are measured. The time averaged results showed that the wake flow become more uniform and the TKE distribution is more concentrated around tip area of the turbine wake as the torque coefficient increase. The measurement of five hole Pitot-tubes were made and exclusive software is developed to analysis the data of 5hole pitot-tube experiment to compared with time-averaged SPIV results at the highest efficiency value of TSR condition. Also angular and radial velocity components were calculated. The results showed that the angular velocity is reversed from the out side of border area of the turbine wake. Also relatively high angular velocity was observed near the wake core and it could be negligible as getting closer to the turbine tip. In addition, efficiency of the turbine and the fluctuation of the velocity has a strong relationship due to the development of strong tip vortices, as observed in phase-averaged velocity fields results. Also to get the high resolution of PIV results, the reiterated cross correlation method is invented and used to developed the PIV data analysis program which can give high resolution PIV results even with one pair of raw data of pictures